It is often advantageous for systems and/or machines to provide some indication of an operational status or of an executing operation to users of the system. In a similar manner, providing an indication of the system to external observers may also be beneficial. For example, operators of vehicles often provide some indication of an intended maneuver of the vehicle, such as by initiating a turn signal before making a lane change. Such an indication alerts other nearby drivers or pedestrians to the intention of the driver of the vehicle such that the other nearby drivers and pedestrians may react accordingly. Further, many drivers provide other, more subtle cues as the intention of the driver while operating the vehicle that are viewed and considered by the other nearby drivers and pedestrians when reacting to the operation of the vehicle. For example, multiple views in a rearview mirror by a driver may indicate the driver intends on changing lanes, regardless of whether the driver uses a turn signal.
Because many drivers rely on these indicators when driving, some are uncomfortable operating a vehicle around autonomous or unmanned vehicles. In particular, many drivers are unsure of the operation of an autonomous vehicle such that they cannot anticipate how the vehicle is going to move in traffic and fail to react normally to the presence of the autonomous vehicle while driving. This may lead to avoidable collisions between cars and unsafe driving conditions. Thus, providing indications of the operation of the autonomous vehicle aids other drivers and pedestrians in anticipating the movement of the autonomous vehicle and, ultimately, makes such observers more comfortable with the presence of the autonomous vehicles on the roads.